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Abstract:

Apparatus and methods are described for laser ablation of tissue. The
apparatus and methods utilize a laser source coupled to a fiberoptic
laser delivery device and a laser driver and control system with features
for protection of the laser delivery device, the patient, the operator
and other components of the laser treatment system. Advantageously, the
laser source may utilize laser diodes operating at approximately 975 nm,
1470 nm, 1535 nm or 1870 nm wavelengths with a laser power output of at
least 60 watts, preferably greater than 80 watts and most preferably
120-150 watts or higher. The invention, which has broad medical and
industrial applications, is described in relation to a method for
treatment of benign prostatic hyperplasia (BPH) by contact laser ablation
of the prostate (C-LAP).

Claims:

1. Apparatus for laser treatment of tissue, comprising: a laser
configured to produce an output beam; an optical fiber having a proximal
end and a distal end; a connector configured to couple the output beam of
the laser into the proximal end of the optical fiber; a beam-emitting
distal tip located proximate the distal end of the optical fiber; an
optical fiber protection system including an infrared detector configured
to detect a magnitude of an infrared signal emitted from the proximal end
of the optical fiber; and means for determining a rate of rise of the
infrared signal emitted from the proximal end of the optical fiber.

2. The apparatus of claim 1, further comprising: means for correlating
the magnitude of the infrared signal emitted from the proximal end of the
optical fiber with a temperature of the optical fiber; and means for
modulating the output beam of the laser to maintain the temperature of
the optical fiber within a predetermined temperature range.

3. The apparatus of claim 2, further comprising: means to shut down
operation of the laser when the temperature of the optical fiber exceeds
a predetermined temperature threshold that is potentially destructive to
the optical fiber.

4. The apparatus of claim 1, further comprising: means to shut down
operation of the laser when the magnitude of the infrared signal emitted
from the proximal end of the optical fiber exceeds a predetermined
threshold indicating a condition that is potentially destructive to the
optical fiber.

5. The apparatus of claim 1, further comprising: means for correlating
the rate of rise of the infrared signal emitted from the proximal end of
the optical fiber with an operating condition of the optical fiber; and
means for shutting down operation or alerting a user when the operating
condition of the optical fiber is not within a predetermined range for
the operating condition.

6. The apparatus of claim 1, further comprising: means to shut down
operation of the laser when the rate of rise of the infrared signal
emitted from the proximal end of the optical fiber exceeds a
predetermined rate threshold indicating an operating condition that is
potentially destructive to the optical fiber.

7. The apparatus of claim 1, further comprising: means to shut down
operation of the laser when the magnitude of the infrared signal emitted
from the proximal end of the optical fiber exceeds a predetermined
threshold and the rate of rise of the infrared signal emitted from the
proximal end of the optical fiber exceeds a predetermined rate threshold
indicating a condition that is potentially destructive to the optical
fiber.

8. The apparatus of claim 1, wherein the laser is configured to produce
an output beam of at least 60 watts of power.

9. The apparatus of claim 1, wherein the laser is configured to produce
an output beam of approximately 120-150 watts of power.

10. The apparatus of claim 1, wherein the laser is configured to produce
an output beam with a wavelength of approximately 975 nm.

11. The apparatus of claim 1, wherein the laser is configured to produce
an output beam with a wavelength of approximately 1470 nm.

12. The apparatus of claim 1, wherein the laser is configured to produce
an output beam with a wavelength of approximately 1535 nm.

13. The apparatus of claim 1, wherein the laser is configured to produce
an output beam with a wavelength of approximately 1870 nm.

14. The apparatus of claim 1, wherein the optical fiber protection system
further comprises: a beam splitter or partially reflective mirror
disposed in the laser beam path and configured to reflect infrared
radiation from the proximal end of the optical fiber toward the infrared
detector.

15. The apparatus of claim 1, wherein the optical fiber protection system
further comprises: a second optical fiber coupled to the proximal end of
the optical fiber and configured to direct infrared radiation from the
proximal end of the optical fiber toward the infrared detector.

16. The apparatus of claim 1, wherein the optical fiber protection system
further comprises: a filter configured to allow infrared radiation from
the proximal end of the optical fiber to pass to the infrared detector
and to prevent radiation at the operating wavelength of the laser source
from passing to the infrared detector.

17. The apparatus of claim 1, wherein the laser is configured to produce
a pulsed output beam, and wherein the infrared detector is adapted to
detect the magnitude of the infrared signal emitted from the proximal end
of the optical fiber during an off period between pulses of the pulsed
output beam.

18. The apparatus of claim 17, further comprising: means for modulating
the output beam of the laser to reduce an average power of the output
beam when the magnitude of the infrared signal emitted from the proximal
end of the optical fiber exceeds a predetermined threshold.

19. The apparatus of claim 18, further comprising: means for modulating
the output beam of the laser to increase the average power of the output
beam when the magnitude of the infrared signal emitted from the proximal
end of the optical fiber is lower than a predetermined value.

20. The apparatus of claim 18, wherein the means for modulating the
pulsed output beam of the laser reduces the average power of the pulsed
output beam by reducing the duration of each pulse.

21. The apparatus of claim 18, wherein the means for modulating the
output beam of the laser reduces the average power the output beam by
reducing the peak power of the output beam.

22. The apparatus of claim 1, wherein the beam-emitting distal tip
includes a fiber tip member fused to the distal end of the optical fiber,
the fiber tip member having a diameter greater than a diameter of the
optical fiber, and a tubular member surrounding the fiber tip member and
fused to the fiber tip member.

23. The apparatus of claim 22, wherein the fiber tip member comprises a
plug of optical material having a diameter greater than the diameter of
the optical fiber and fused to the distal end of the optical fiber.

24. The apparatus of claim 22, wherein the fiber tip member is formed by
melting the distal end of the optical fiber to form a fiber tip member
with a diameter greater than the diameter of the optical fiber and
integral to the distal end of the optical fiber.

25. The apparatus of claim 22, wherein the optical fiber, the fiber tip
member and the tubular member have approximately the same refractive
index.

26. The apparatus of claim 25, wherein the optical fiber, the fiber tip
member and the tubular member are made of fused quartz.

27. The apparatus of claim 22, wherein the optical fiber is configured
with a forward-firing straight beam-emitting distal tip.

28. The apparatus of claim 22, wherein the optical fiber is configured
with a forward-firing bent beam-emitting distal tip.

29. The apparatus of claim 22, wherein the optical fiber is configured
with a reflective side-firing beam-emitting distal tip.

30. The apparatus of claim 29, wherein the reflective side-firing
beam-emitting distal tip further comprises a lens fused to a side of the
tubular member.

31. The apparatus of claim 1, wherein the laser comprises a diode laser.

32. The apparatus of claim 1, wherein the laser comprises a fiber laser.

34. The apparatus of claim 1, wherein the laser comprises a continuous
wave laser modulated to form a pulsed output beam.

35. The apparatus of claim 34, further comprising: means for modulating
the output beam of the laser to reduce power of the output beam when the
magnitude of the infrared signal emitted from the proximal end of the
optical fiber exceeds a predetermined threshold.

36. The apparatus of claim 34, further comprising: means for modulating
the output beam of the laser to reduce an average power of the output
beam by reducing a duration of each pulse when the magnitude of the
infrared signal emitted from the proximal end of the optical fiber
exceeds a predetermined threshold.

37. The apparatus of claim 34, further comprising: means for modulating
the output beam of the laser to reduce an average power of the output
beam by reducing the peak power of each pulse when the magnitude of the
infrared signal emitted from the proximal end of the optical fiber
exceeds a predetermined threshold.

38. The apparatus of claim 35, further comprising means for indicating to
a user when the power of the output beam has been reduced below a
predetermined tissue vaporization threshold.

39. The apparatus of claim 35, further comprising means to shut down
operation of the laser when the infrared radiation from the proximal end
of the optical fiber exceeds a second predetermined threshold indicating
an operating condition that is potentially destructive to the optical
fiber.

40. The apparatus of claim 35, further comprising means to shut down
operation of the laser when the infrared radiation from the proximal end
of the optical fiber exceeds a third predetermined threshold indicating
potential damage or contamination of the proximal end of the optical
fiber.

41. The apparatus of claim 40, further comprising: means for indicating
to a user that the proximal end of the optical fiber is potentially
damaged.

42. The apparatus of claim 1, further comprising a scope protection
system that includes: a photodetector configured to detect visible light
emitted from the proximal end of the optical fiber; and means for
preventing operation of the laser when the detected level of visible
light emitted from the proximal end of the optical fiber is below a
predetermined level indicating that the beam-emitting distal tip of the
optical fiber is inside of an endoscope channel.

43. The apparatus of claim 42, further comprising: means for preventing
operation of the laser when the detected level of visible light emitted
from the proximal end of the optical fiber is below a second
predetermined level indicating a crack or other potential damage in the
optical fiber; and means for indicating to a user that the optical fiber
is potentially damaged.

44. The apparatus of claim 1, further comprising a scope protection
system that includes: a photodetector configured to detect visible light
emitted from the proximal end of the optical fiber; means for determining
a rate of change of the visible light detected by the photodetector; and
means for preventing operation of the laser when the detected level of
visible light emitted from the proximal end of the optical fiber drops
below a predetermined level at a rate higher than a rate indicating that
the beam-emitting distal tip of the optical fiber has been withdrawn into
an endoscope channel.

45. The apparatus of claim 44, further comprising: means for preventing
operation of the laser when the detected level of visible light emitted
from the proximal end of the optical fiber drops below a predetermined
level at a rate higher than a rate indicating a crack or other potential
damage in the optical fiber; and means for indicating to a user that the
optical fiber is potentially damaged.

46. The apparatus of claim 1, further comprising: a blast shield
interposed between the laser and the proximal end of the optical fiber;
an infrared sensor configured to sense an infrared radiation emitted by
the blast shield; and means to renew the blast shield when the infrared
radiation emitted by the blast shield exceeds a predetermined threshold.

47. The apparatus of claim 46, wherein the means to renew the blast
shield rotates the blast shield when the infrared radiation emitted by
the blast shield exceeds a predetermined threshold.

48. The apparatus of claim 46, wherein the means to renew the blast
shield moves the blast shield when the infrared radiation emitted by the
blast shield exceeds a predetermined threshold.

49. The apparatus of claim 46, further comprising: means for preventing
operation of the laser when the infrared sensor senses a second
occurrence of the infrared radiation emitted by the blast shield
exceeding the predetermined threshold within a predetermined time
interval after renewing the blast shield indicating potential damage in
the optical fiber; and means for indicating to a user that the optical
fiber is potentially damaged.

50. The apparatus of claim 1, further comprising: an ambient or stray
beam detector; means for stopping operation of the laser when an ambient
or stray laser beam is detected.

51. The apparatus of claim 1, further comprising: data recording means
associated with the optical fiber for recording data related to a
procedure performed using the optical fiber.

52. The apparatus of claim 51, wherein the data recording means is
located in the connector at the proximal end of the optical fiber.

53. The apparatus of claim 51, wherein the data recording means is
configured to record the date and time of the procedure, total energy
laser used, error code logs from the laser, preventive maintenance logs
from the laser, and the number of cases the laser has been used in.

54. The apparatus of claim 1, further comprising: a resecting loop for
removal of additional tissue after vaporization of tissue using the
laser.

55. (canceled)

56. (canceled)

57. (canceled)

58. (canceled)

59. (canceled)

60. (canceled)

61. (canceled)

62. (canceled)

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to apparatus and methods for laser
ablation of tissue. The apparatus and methods utilize a laser source
coupled to a fiberoptic laser delivery device and a laser driver and
control system with features for protection of the laser delivery device,
the patient, the operator and other components of the laser treatment
system. The invention, which has broad medical and industrial
applications, is described in relation to a method for treatment of
benign prostatic hyperplasia (BPH) by contact laser ablation of the
prostate (C-LAP).

BACKGROUND OF THE INVENTION

[0002] The present invention has broad applications in surgery and other
medical procedures for ablation, i.e. removal of obstructive or unwanted
tissue, by tissue vaporization. One important application of the
invention is for treatment of prostate enlargement or benign prostatic
hyperplasia (BPH). BPH is a common condition in men over the age of 50
that occurs when nodular tissue from the prostate gland grows into and
obstructs the urethra. BPH is characterized by difficulty urinating and a
variety of other related symptoms.

[0003] Transurethral resection of the prostate (TURP) has been the most
common surgical procedure for BPH. A resectoscope is inserted into the
penis through the urethra and up to the prostate gland and an
electrically heated wire loop is used to remove tissue from the interior
of the prostate gland. TURP is considered by some to be the "gold
standard" in treatment of BPH because it provides reliable symptomatic
relief and can be used in large, as well as small prostate glands.
However, there are significant drawbacks to the procedure. TURP is
performed using spinal or general anesthesia and a 1-3 day hospital stay
is generally required. A urinary catheter must be left in place for at
least 1-3 days after surgery and the recovery time is typically four to
six weeks. The known side effects of TURP include excessive bleeding,
frequent urge to urinate, retrograde ejaculation, erection problems,
painful urination (dysuria), recurring urinary tract infections, bladder
neck narrowing (stricture), and blood in the urine (hematuria).

[0004] For these reasons, recent efforts have been focused on developing
less invasive methods of treating BPH, including various methods of laser
prostatectomy. The research goal has been to develop methods that are as
effective as the "gold standard" of TURP in relieving symptoms, but are
less traumatic to the patient and have fewer side effects.

[0005] One known method of performing laser prostatectomy involves using a
laser for coagulation of the enlarged prostate tissue. Using a fiberoptic
laser delivery device, the tissue to be removed is coagulated to kill the
tissue. In one variation of this procedure, the laser energy is directed
at four regions of the prostate tissue designated as the 2, 4, 8 and 10
o'clock positions. The tissue coagulation results in an immediate
swelling of the surrounding tissue, therefore a catheter is allowed to
remain in place for several days following the operation to allow for
drainage of urine. Once the swelling subsides, the catheter is removed
and over a period of several weeks the dead tissue sloughs off naturally,
leaving an open passage through the urethra. Although this approach has
been shown to be effective, it has the distinct disadvantage that the
results are not immediate. The patient must endure the discomfort and
inconvenience of having a catheter placed in the urethra for a number of
days. In addition, some patients will experience continued dysuria or an
inability to void after the catheter is removed.

[0006] Because of the shortcomings of the laser coagulation approach,
recent efforts have been directed toward developing a method called
photoselective vaporization of the prostate (PVP). Theoretically, if the
enlarged prostate tissue can be completely removed at the time of
treatment, then the patient should experience immediate relief from many
of the symptoms. One laser that has been evaluated for this procedure is
a frequency-doubled Nd:YAG laser. The 1064 nm beam of a Nd:YAG laser is
directed through a nonlinear optical element, such as Potassium Titanyl
Phosphate (KTiOPO4 or KTP) or Potassium Dihydrogen Phosphate (KDP),
which absorbs the laser radiation and reemits it at twice the frequency
(that is, half the wavelength) resulting in a 532 nm visible green light
beam.

[0007] The 532 nm beam of the frequency-doubled Nd:YAG laser has a high
absorption in the oxyhemoglobin component of blood. Since blood is the
target chromophore of the 532 nm wavelength, the first pass of the laser
results in ablation and carbonization of the surface tissue. However, the
underlying tissue is devascularized, resulting in reduced ablation
efficiency of the 532 nm wavelength on subsequent passes of the laser.
From the procedural point of view, after the first pass using a 532 nm
wavelength laser for BPH, the tissue blanches and it becomes increasingly
difficult to vaporize additional tissue. Completion of the procedure will
require an increase in the power setting of the laser, if more power is
available, or will require more procedural time at the lower tissue
ablation rate. Various scientific and clinical papers have reported that,
as a result of the decreased ablation efficiency, 532 nm wavelength laser
systems do not perform well with large prostate glands greater than 50
gm. For example, Tugcu et al. reported that in a series of 100 patients
with prostate glands ranging from 74-170 ml, a procedure time of 100-240
minutes was required for ablation using an 80 watt "KTP laser" (Urologia
Internationalis 2007; 79:316-320).

[0008] The efficiency of the laser system at vaporizing tissue is also
adversely affected by fowling of the fiber tip with tissue, char or other
material. Once the fiber tip has been contaminated, the temperature of
the fiber will quickly rise with added laser energy and thermal runaway
could result in damage or destruction of the fiber. For this reason, the
532 nm wavelength laser is recommended only for non-contact vaporization
of the prostate. Yet, at the same time, for effective tissue
vaporization, the fiber tip must be maintained a distance of
approximately 1 mm or less from the tissue surface without contacting it.
In practice, this is quite difficult and requires a great deal of
training and practice on the part of the surgeon.

[0009] Others have reported using a 100 watt holmium laser to treat BPH in
a procedure called Holmium Laser Assisted Prostatectomy, or HoLAP. The
Holmium laser at 2100 nm is highly absorbed in water, and it will ablate
any tissue with even a small amount of water contained in it. Water
exists in all cells. Holmium laser treatment for BPH is conducted with
water as an irrigant; therefore the laser energy has to pass through
water to reach its intended target. Thus, a significant amount of laser
energy is lost just getting the beam to the prostate tissue. On the plus
side, the extremely high absorption of the 2100 nm holmium laser energy
by water means that almost all of the laser energy that reaches the
tissue is used in ablation or vaporization of the tissue. Very little
energy is left over to cause thermal damage and coagulation in
surrounding tissue. This leads to what holmium researchers refer to as
the WYSIWYG (What you see is what you get.) effect, meaning that the
result seen through the cystoscope at the end of the procedure is in
effect the final result because there will not be a significant amount of
tissue sloughing off later due to coagulation. However, the extremely
high absorption of the 2100 nm holmium laser energy at high peak power
combined with the pulsed delivery also results in what some doctors have
referred to as the "clam chowder" effect. The tissue gets chewed up by a
multitude of tiny explosions within the tissue. After the first pass with
the laser delivery device the tissue surface is pocketed with ablation
craters, therefore a higher and higher percentage of the laser pulses is
directed into a crater and is absorbed by the irrigation fluid so that it
never reaches the tissue, which reduces ablation efficiency. In addition,
while these tiny explosions are ablating tissue they are violent enough
that bleeding occurs and, since there is not much tissue heating, there
is not enough coagulation to control bleeding well. Additionally, while
the holmium laser ablates tissue very well regardless of the presence of
blood in the gland, it does so at significantly lower tissue penetration
depth and lower tissue vaporization rate than the 532 nm laser, requiring
even longer procedure times.

[0011] The present invention provides apparatus and methods for laser
ablation of tissue. The apparatus includes a laser treatment system with
a laser source coupled to a fiberoptic laser delivery device and a laser
driver and control system for operating the laser source. The laser
driver and control system implements a number of safety features for
protection of the laser delivery device and other components of the laser
treatment system. The laser driver and control system provides a number
of advantages over the prior art. In particular, it allows the laser
treatment system to be used for a method of contact laser vaporization of
tissue. As noted above, many prior laser systems were limited to
non-contact ablation methods because contamination of the fiberoptic
laser delivery device with tissue or other matter would cause thermal
runaway, quickly leading to destruction of the optical fiber. This
problem is especially prevalent with high power laser sources (above
about 50 watts), which is necessary for effective vaporization of tissue.
The laser control system monitors the temperature and the operating
condition of the fiberoptic laser delivery device and modulates the
output beam to maintain the temperature below a predetermined threshold
temperature or within a predetermined temperature range and alerts the
user when the operating condition of the fiberoptic laser delivery device
is not within a predetermined range for safe operation. The laser control
system operates so as to maintain effective tissue vaporization without
causing thermal runaway and damage to the fiberoptic laser delivery
device. In addition, the laser driver and control system monitors other
parameters of the laser treatment system for use by a proximal surface
protection system, a blast shield protection system, a scope protection
system, a fiber breakage detector and an ambient beam sensor.

[0012] The apparatus and methods of the present invention can be used with
any type of laser that can be transmitted by a fiberoptic laser delivery
device and that provides a combination of a suitable wavelength and
sufficient power for tissue vaporization. Suitable laser sources include,
but are not limited to: Ho:YAG laser, CTH:YAG laser, Nd:YAG laser, Er:YAG
laser, frequency-doubled Nd:YAG laser, fiber lasers of various
wavelengths, and direct diode lasers of various wavelengths.

[0013] One particularly preferred embodiment of the laser treatment system
of the present invention utilizes a diode laser operating at a wavelength
of approximately 750-2000 nm. Within this range, there are a number of
commercially available laser diodes that are suitable for use in the
laser treatment system, including laser diodes operating at approximately
975 nm, 1470 nm, 1535 nm and 1870 nm wavelengths (+/-20 nm). The laser
treatment system will preferably be capable of a laser power output of at
least 60 watts, preferably greater than 80 watts and most preferably
120-150 watts or higher. A laser treatment system specially adapted for
performing contact laser tissue ablation, the VECTRA 120, been developed
by Convergent Laser Technologies of Alameda, Calif. and will soon be
available for clinical use.

[0014] The wavelength of a laser strongly affects the interaction of the
laser beam with tissue. In particular, the specific absorption
characteristics of the laser wavelength in various target chromophores
present in the tissue affects the depth of penetration and the ability to
coagulate and/or vaporize tissue. Examples of target chromophores that
can be present in the tissue include water, hemoglobin and melanin. In
addition, dyes can be added to the tissue to increase absorption of
certain wavelengths. Charring of tissue generally increases the energy
absorption at all wavelengths. At low power densities, lasers are
typically effective at coagulating tissue, but at higher power densities,
above a certain threshold level, some lasers become more effective at
ablating or vaporizing tissue. A small amount of beneficial tissue
coagulation typically occurs outside of the tissue vaporization region.
Generally, the higher the power density of the laser beam delivered at
the tissue surface, the higher the ratio of tissue vaporization to
coagulation will be. The tissue vaporization threshold varies depending
on the wavelength, the tissue type, the delivery method and the beam
power density at the tissue surface; however it can be determined
empirically for a given combination of these parameters. For contact
tissue vaporization using a diode laser delivered though a fiberoptic
laser delivery device as described herein for treatment of prostate
tissue, reaching the tissue vaporization threshold typically requires
approximately 60-80 watts of laser energy. By operating the laser above
the tissue vaporization threshold, the laser treatment system of the
present invention using a fiberoptic laser delivery device in tissue
contact mode provides an effective treatment for benign prostatic
hyperplasia by tissue vaporization.

[0015] The method of contact tissue vaporization of the present invention
has a number of advantages over the prior art approaches that rely solely
on non-contact tissue vaporization. The fiberoptic laser delivery device
is designed to provide more contact area between the beam-emitting tip
and the tissue than previous fiberoptic devices in order to maximize
ablation. Direct contact allows efficient transmission of laser energy to
the tissue without it being absorbed by the irrigation fluid or by
turbidity in the irrigation fluid that can occur during laser ablation.
The result is a marked amplification of the ablation or tissue
vaporization effect of the laser and an increase in the ratio of tissue
vaporization to coagulation for a given power level. Maintaining a close
spacing between the laser delivery device and the tissue without
inadvertent contact is quite challenging, whereas the simple pull-back
motion used in the contact tissue vaporization method is easier to
perform and has a much quicker learning curve for urologists who have
been trained in the classic TURP technique. However, the contact tissue
vaporization method places quite a bit more thermal stress and mechanical
stress on the laser delivery device. It is a major inconvenience to the
user to have a procedure interrupted because the laser delivery device
has failed or has became too ineffective to achieve tissue vaporization.
In addition, users will resist the additional cost of replacing the laser
delivery device midway through a procedure. Success of the contact tissue
vaporization method can thus be enhanced by using a more durable and
efficient laser delivery device. More efficient laser transmission and
distribution of any heat generated will reduce the thermal stress on the
laser delivery device and a more durable construction will help it to
resist both thermal and mechanical stresses. To this end, the present
invention also provides a highly robust and durable fiberoptic laser
delivery device that is constructed to minimize transmission losses and
to dissipate heat buildup in the device, making it suitable for contact
tissue vaporization. This more robust and durable fiberoptic laser
delivery device coupled with the laser driver and control system of the
invention provides a very reliable laser treatment system for contact
tissue vaporization.

[0016] The invention, which has broad medical and industrial applications,
is described in relation to a method for treatment of benign prostatic
hyperplasia (BPH) by contact laser ablation of the prostate (C-LAP). The
C-LAP procedure operates by vaporization of prostate tissue that is
obstructing the lumen of the urethra and/or by debulking the tissue of
the prostate to open the lumen of the urethra. The laser treatment system
and the methods of contact laser tissue ablation of the present invention
have numerous other applications in urology, gastroenterology,
dermatology, cardiovascular treatments and many other areas of surgery
and medical treatment. The laser treatment system can also be used for
tissue welding and interstitial tissue treatments.

[0017] Numerous other advantages and features of the present invention
will become readily apparent from the following detailed description of
the invention and the embodiments thereof, from the claims and from the
accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIGS. 1A-1E show representative front and side view drawings of the
diode laser system for C-LAP of the present invention, both on a mobile
cart system and standing alone.

[0019]FIG. 2 is a representative schematic illustration of a fiberoptic
laser delivery device for use in the method for contact tissue ablation
of the present invention.

[0020]FIG. 3 is a representative schematic drawing showing a functional
block diagram of the method and apparatus of the present invention for
performing contact laser tissue ablation.

[0021] FIG. 4A is a schematic diagram of an optical system for use in the
present invention.

[0022] FIG. 4B is a schematic diagram of an alternate optical system for
use in the present invention.

[0024] FIG. 6 is a longitudinal cross section of a bent tip fiberoptic
laser delivery device with a bent portion ending in a beam-emitting
distal surface.

[0025] FIG. 7 is a longitudinal cross section of another fiberoptic laser
delivery device having a side-firing tip with an angled reflective
surface that redirects the laser beam out through a beam-emitting lateral
surface.

[0026] FIG. 8 is a longitudinal cross section of another fiberoptic laser
delivery device having a side-firing tip with an angled reflective
surface that redirects the laser beam out through a lens on the lateral
surface of the device.

[0027] FIGS. 9A-9C illustrate representative steps for performing contact
laser ablation of the prostate using the apparatus and methods of the
present invention.

[0028] FIGS. 10A-10D illustrate an example of a method of performing C-LAP
according to the present invention.

[0029] FIG. 11 is a representative schematic illustration of a wire loop
for performing TURP in conjunction with the method and apparatus for
C-LAP of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0030] The description that follows is presented to enable one skilled in
the art to make and use the present invention, and is provided in the
context of a particular application and its requirements. Various
modifications to the disclosed embodiments will be apparent to those
skilled in the art, and the general principles discussed below may be
applied to other embodiments and applications without departing from the
scope and spirit of the invention. Therefore, the invention is not
intended to be limited to the embodiments disclosed, but the invention is
to be given the largest possible scope which is consistent with the
principles and features described herein.

[0031] It will be understood that in the event parts of different
embodiments have similar functions or uses, they may have been given
similar or identical reference numerals and descriptions. It will be
understood that such duplication of reference numerals is intended solely
for efficiency and ease of understanding the present invention, and are
not to be construed as limiting in any way, or as implying that the
various embodiments themselves are identical.

[0032] The apparatus and methods of the present invention can be used with
any type of laser that can be transmitted by a fiberoptic laser delivery
device and that provides a combination of a suitable wavelength and
sufficient power for tissue vaporization. Suitable laser sources include,
but not limited to:

[0033] In one particularly preferred embodiment, the laser treatment
system of the present invention utilizes a diode laser operating at a
wavelength of approximately 750-2000 nm. Within this range, there are a
number of laser diodes currently available that are suitable for use in
the laser treatment system, including laser diodes operating at
approximately 975 nm, 1470 nm, 1535 nm and 1870 nm wavelengths (+/-20
nm). The laser treatment system will preferably be capable of a laser
power output of at least 60 watts, preferably greater than 80 watts and
most preferably 120-150 watts or higher. A laser treatment system
specially adapted for performing contact laser tissue ablation, the
VECTRA 120, been developed by Convergent Laser Technologies of Alameda,
Calif. and will soon be available for clinical use.

[0034] The choice of which laser to use in the laser treatment system of
the present invention depends on a combination of technical, clinical and
economic factors. The output beam of the 1535 nm (+/-20 nm) wavelength
laser diode has high absorption in tissue due to a local maximum in the
absorption spectrum of water, resulting in a relatively low tissue
penetration and a very good ratio of tissue vaporization to coagulation
above the vaporization threshold. The output beam of the 1870 nm (+/-20
nm) wavelength laser diode has nearly identical absorption in water and
in tissue, but at a somewhat higher cost. The output beam of the 1470 nm
(+/-20 nm) wavelength laser diode has very high absorption in tissue due
to another local maximum in the absorption spectrum of water, resulting
in a relatively low tissue penetration and a very good ratio of tissue
vaporization to coagulation above the vaporization threshold, but at a
significantly higher cost. However, new manufacturing technology and/or
market forces could bring the price down to make one of these an
attractive alternative to use in the laser treatment system. The 975 nm
(+/-20 nm) laser diode is currently the lowest cost option capable of
producing the necessary output power for effective tissue vaporization.
The 975 nm wavelength output beam has good absorption in water,
hemoglobin and melanin, resulting in controlled tissue penetration and a
good ratio of tissue vaporization to coagulation above the vaporization
threshold. This combination of features makes it another attractive
alternative to use in the laser treatment system.

[0035] Fiber lasers provide a highly collimated output beam and therefore
high power density, which is very beneficial for tissue vaporization. The
output beam of the 1940 nm (+/-20 nm) fiber laser is also highly absorbed
in water and therefore tissue. Currently, fiber laser technology is very
expensive, but as the cost comes down this could be another attractive
alternative to use in the laser treatment system.

[0036] For all of the wavelengths mentioned, the contact tissue
vaporization method described herein enhances the effectiveness for
tissue vaporization. The initial charring or carbonization of tissue
increases light absorption at all wavelengths, which also enhances the
effectiveness for tissue vaporization.

[0037] The laser treatment system of the present invention may also
utilize two or more wavelengths of laser energy in combination.

[0038] FIGS. 1A-1E show representative front and side view drawings of the
diode laser system 100, both on a mobile cart system 98 and standing
alone. One of the advantages of the diode laser system 100 for performing
contact tissue ablation is that it provides effective tissue vaporization
throughout the procedure when it is operated at a power level above the
tissue vaporization threshold. Higher tissue removal efficiency will
result in shorter procedure time. Additionally, the contact tissue
ablation method of the present invention causes no bleeding because there
is a small amount of beneficial tissue coagulation that occurs outside of
the tissue vaporization region. The contact tissue ablation method is
particularly adaptable to treatment of BPH where these factors combine to
provide immediate and effective relief of symptoms in BPH with a low
incidence of undesirable side effects.

[0039] The diode laser system 100 is small, compact, portable and at only
about 60 pounds, weighs a fraction of what a typical laser of comparable
output power weighs. The diode laser system 100 in its current
configuration is about 19''W×26''L×13''H. In a preferred
embodiment, a rolling cart 98 makes it convenient to roll the laser 100
from place to place, as may be desired. Preferably, the diode laser
system 100 contains an LCD display or other graphical user interface
portion 102 for displaying operating parameters and accepting user
commands, etc. In a preferred embodiment, the graphical user interface
102 can be folded closed for storage or transport, as shown in FIG. 1C,
or raised into an operating and viewing position, as shown in the other
figures. A laser connector port 110 is adapted for receiving any suitable
connector for coupling the laser energy created by the diode laser system
100 to a fiberoptic laser delivery device 200, such as shown in FIG. 2.

[0040] Due to its efficient operation, the diode laser system 100 has very
low electrical power requirements compared to other laser systems of
comparable output power. Consequently, it can be powered from a standard
100-250 volt, single phase 50/60 Hz AC electric power outlet, although it
could readily be adapted to be used with other AC or DC power sources.
Depending on local safety regulations, the diode laser system 100 may
utilize a hospital-style locking power plug. Typically, there is no
external cooling required for the diode laser system 100.

[0041]FIG. 2 is a representative schematic illustration of a fiberoptic
laser delivery device 200 for use in the method for contact tissue
ablation of the present invention. The fiberoptic laser delivery device
200 utilizes an optical fiber 204, which is preferably constructed with a
fused silica or quartz glass core, surrounded by a glass or plastic
cladding and a protective plastic jacket. At the proximal or receiving
end 202 of the optical fiber 204 there is a releasable optical fiber
connector 206, typically an SMA or STC connector, which are standard in
the industry. Alternatively a proprietary connector may be used. The
optical fiber 204 is provided with a beam-emitting tip 208 located
proximate the distal end 210 of the fiber 204, which may be configured as
a straight tip, a bent tip or an angle-firing tip.

[0042] Also shown is a handle or positioning apparatus 212 for use when
the device is inserted through the lumen of a viewing scope or working
endoscope for certain types of procedures. The distance through which the
beam-emitting tip 208 is inserted into a cannula or channel of an
endoscope can be adjusted and precisely positioned by the surgeon during
a surgical operation. It can also serve as a handle or gripping system
212 for the fiber 204 in microprocessor based automated procedures. One
such apparatus 212 would be made of two sections which can be screwed
together to tighten around the jacket of the optical fiber or loosened
for axial repositioning with a slight twist.

[0043] In one particularly preferred embodiment, the fiberoptic laser
delivery device 200 includes a data recording device for recording data
related to a procedure performed using the device 200. The data recording
device may be a flash memory chip or the like and may be housed in the
connector 206 at the proximal end of the optical fiber. One or more
electrical connections on the connector 206 allow the data recording
device to communicate with the laser system. The data recording device is
preferably configured to record the date and time of the procedure, total
energy laser used, error code logs from the laser, preventive maintenance
logs from the laser, and the number of cases the laser has been used in.
The data recording device allows better communication between the user
and the manufacturer or distributor. The fiberoptic laser delivery device
200 or at least the connector 206 with the data recording device can be
returned to the manufacturer or distributor to download the recorded
data. The information gathered can be used to maintain inventories of
fiberoptic laser delivery devices 200 and other accessories or
consumables and to schedule laser system repairs and maintenance. The
data recording device can also be used to facilitate a per case pricing
program for the laser treatment system and/or the fiberoptic laser
delivery devices 200 and other accessories or consumables. In a per case
pricing program, the data recording device can be used to determine
and/or to corroborate how many fiberoptic laser delivery devices 200 have
been used in a given procedure. Based on this information, users can
receive a refund or replacement of a fiberoptic laser delivery device 200
when more than one device was required for a given procedure.

[0044]FIG. 3 is a representative schematic drawing showing a functional
block diagram 400 of the laser treatment system of the present invention
configured for contact laser ablation of tissue. The laser treatment
system includes a laser source 100 that produces an output beam, which is
directed through an optical system 440. The optical system 440 processes
the output beam and delivers it to a fiberoptic laser delivery system 200
through a coupling device 430. The coupling device 430 is typically an
SMA or STC releasable connector. The fiberoptic delivery system 200
conducts the laser energy to a beam-emitting tip 208. In addition, the
optical system 440 provides feedback signals that are directed to the
laser driver and control system 410, which is used to control the laser
source 100.

[0045] When the laser treatment system is configured for contact laser
ablation of the prostate (C-LAP), it will typically utilize a cystoscope
or resectoscope 300 for visualizing the procedure. The tubular insertion
portion 302 of the cystoscope 300 is placed in the urethra and the
fiberoptic delivery system 200 is inserted through a working channel in
the cystoscope 300.

[0046] FIG. 4A is a schematic diagram of the optical system 440 shown in
FIG. 3. The configuration of the optical system 440 shown is given as an
example; one of ordinary skill in the art will recognize that variations
can be made to the configuration for accomplishing the intended outcome.
The output beam from the laser source 100 enters the optical system 440
on the left of the diagram and passes through a beam expander/collimator
442. The optical components of the beam expander/collimator 442
preferably have an antireflective coating to maximize transmission at the
laser output wavelength. The expanded and collimated beam then passes
through a beam-splitter 444 positioned at an angle to the beam. The
beam-splitter 444 preferably has an antireflective coating to maximize
transmission at the laser output wavelength at the angle of incidence and
the distal surface (right side in the diagram) will also have a
reflective coating for wavelengths above 1200 nm at the angle of
incidence. The beam then passes through a beam-combiner 448 and the laser
output beam is combined with an aiming beam from an emitter 446 that
emits a beam of visible light, for example, a low power 532 nm (green)
diode pumped solid state (DPSS) laser. The beam-combiner 448 preferably
has an antireflective coating to maximize transmission at the laser
output wavelength at the angle of incidence and the distal surface (right
side in the diagram) will also have a reflective coating for the
wavelength of the aiming beam (e.g. 532 nm) at the angle of incidence.
The beam-combiner 448 will also be at least partially transmissive of
wavelengths above 1200 nm at the angle of incidence, which may also be
accomplished with an antireflective coating if required. The combined
beams pass through a beam expander/collimator 450, reversed to compress
the beams and focus them on the proximal end 202 of the optical fiber
204. The optical components of the beam expander/collimator 450
preferably have an antireflective coating to maximize transmission at the
laser output wavelength and are at least partially transmissive of the
532 nm wavelength and wavelengths above 1200 nm.

[0047] Light returning from the proximal end 202 of the optical fiber 204
passes in the reverse direction through the beam expander/collimator 450
and the beam-combiner 448 and is reflected by the reflective coating on
the beam-splitter 444. The returning light is directed through a
filter-splitter 452, which separates the visible wavelengths from the
wavelengths above 1200 nm. The wavelengths above 1200 nm are directed
toward an infrared sensor 420 that produces a signal indicative of the
temperature of the beam-emitting tip 208, which is sent to the laser
driver and control system 410. Elevated temperatures of the optical fiber
proximal surface and the blast-shield, if present, will also be detected
by the infrared sensor 420. The visible wavelengths are directed at a
right angle toward a visible light sensor 454 that produces a signal
indicative of the visible light intensity returning from the optical
fiber 204, which is also sent to the laser driver and control system 410.

[0048] FIG. 4B is a schematic diagram of an alternate optical system 440
for use in the present invention. In this illustrative embodiment, the
laser source 100 utilizes fiber-coupled laser diodes that are coupled to
the proximal end 202 of the optical fiber 204. A small diameter optical
fiber 441 (typically 100 microns in diameter) is coupled to the proximal
end 202 of the optical fiber 204. The small diameter optical fiber 441
intercepts a portion of the light returning through the optical fiber 204
and directs it to the infrared sensor 420. A filter may be used to filter
out other wavelengths and allow the infrared light to pass to the
infrared sensor 420. Similarly, a second small diameter optical fiber 443
(typically 100 microns in diameter) is coupled to the proximal end 202 of
the optical fiber 204. The second small diameter optical fiber 443
intercepts a portion of the light returning through the optical fiber 204
and directs it to the visible light sensor 454. A filter may be used to
filter out other wavelengths and allow the visible light to pass to the
visible light sensor 454.

[0049] The laser driver and control system 410 utilizes the signal from
the infrared sensor 420 for the operation of a fiber tip protection
system. The laser driver and control system 410 may be implemented using
a microcontroller. In its current configuration, the fiber tip protection
system must sample the signal from the infrared sensor 420 when the laser
source 100 is off because the signal-to-noise ratio is overwhelmed by the
high power of the laser's output beam when it is on. For pulsed lasers,
the fiber tip protection system samples the signal from the infrared
sensor 420 during the off portion of the pulse cycle. For continuous wave
(CW) lasers, such as the diode lasers described above, the laser source
100 may be turned off briefly or the output beam interrupted to allow
sampling of the signal from the infrared sensor 420. To accomplish this,
the continuous wave laser is modulated in a pulsatile manner and the
signal from the infrared sensor 420 is sampled during the off portion of
the pulse cycle. In the currently preferred embodiment, the sampling
occurs at a rate of approximately 100 Hz.

[0050] Alternatively, a filter may be provided to filter out other
wavelengths, particularly the output wavelength of the laser source, from
the infrared signal, thus allowing the continuous wave laser to be
operated without interruption. In this case, the laser source can be
operated in a continuous wave mode as long as the temperature threshold
T1 of the fiberoptic laser delivery device 200 is not exceeded. To
maintain the temperature of the fiberoptic laser delivery device 200
below T1, the laser driver and control system 410 can reduce the average
power of the laser output beam by either reducing the peak power and/or
by pulse modulating the beam in order to maintain the peak power density
above the tissue vaporization threshold.

[0051] The magnitude of the signal from the infrared sensor 420 is
indicative of the temperature of the beam-emitting tip 208 of the
fiberoptic laser delivery device 200. The exact relationship between the
temperature of the beam-emitting tip 208 and the magnitude of the signal
from the infrared sensor 420 is somewhat variable depending on the
materials and the configuration of the fiberoptic laser delivery device
200 and the materials and the configuration of the optical system 440.
However, this relationship can be determined empirically for a given
configuration of the laser treatment system, as can the maximum safe
operating temperature or threshold temperature T1 of the fiberoptic laser
delivery device 200. The fiber tip protection system operates to maintain
the temperature of the beam-emitting tip 208 below the threshold
temperature T1 or within a predetermined temperature range while
maximizing the tissue ablation effect of the laser treatment system. The
fiber tip protection system monitors the magnitude of the signal from the
infrared sensor 420 and reduces the average power of the output beam from
the laser source 100 when the temperature approaches the threshold
temperature T1. In a preferred control scheme, this is accomplished by
decreasing the duration of the laser pulses and/or by increasing the off
time between pulses, while maintaining the peak power density above the
tissue vaporization threshold. Optionally, the laser treatment system may
be configured to determine and display the actual temperature of the
beam-emitting tip 208 of the fiberoptic laser delivery device 200.

[0052] When the temperature exceeds a second threshold temperature T2,
which is considered the upper limit for safe operation of the fiberoptic
laser delivery device 200, the fiber tip protection system will shut off
power to the laser source 100 and will alert the user. When the fiber tip
protection system determines that the laser treatment system can no
longer be operated for efficient tissue vaporization, e.g. when the peak
power must be reduced below the tissue vaporization threshold to avoid
exceeding the second threshold temperature T2, it will alert the user and
give the options of changing the fiberoptic laser delivery device 200 or
continuing the procedure with less efficient operation. (If the procedure
is nearly finished or if the procedure can be completed with coagulation
only, the user may elect to continue with the current fiberoptic laser
delivery device 200.)

[0053] In an alternate control scheme, the laser driver and control system
410 can be configured to maintain the temperature of the fiberoptic laser
delivery device 200 within a specified temperature range. The laser power
would be adjusted up or down to keep the fiberoptic laser delivery device
200 within the specified temperature range. The laser driver and control
system 410 would shut off power to the laser source 100 and alert the
user of the fault if the temperature of the fiberoptic laser delivery
device 200 cannot be maintained within the specified temperature range.

[0054] The laser driver and control system 410 also monitors the rate of
rise, that is, the slope or derivative, of the signal from the infrared
sensor 420. The rate of rise of the signal from the infrared sensor 420
is indicative of the operating condition of the fiberoptic laser delivery
device 200 and in particular the beam-emitting tip 208. As the
beam-emitting tip 208 becomes fowled with tissue or other debris or as
microcracks develop from thermal stresses, the temperature of the
beam-emitting tip 208, and hence the infrared signal, will rise more
rapidly for a given level of laser power input. This information can be
used in a number of ways. A threshold value can be empirically determined
for the rate of rise of the signal from the infrared sensor 420 that
indicates impending failure for a given configuration of the laser
treatment system. The laser driver and control system 410 will be
programmed to shut off power to the laser source 100 and alert the user
when the rate of rise of the signal from the infrared sensor 420
approaches or exceeds the threshold value. In addition, the rate of rise
of the signal from the infrared sensor 420 and the magnitude of the
infrared sensor 420 can be used in an algorithm or a lookup table to
determine the power level for operating the laser source 100 for
optimized vaporization of tissue while avoiding thermal runaway and
damage to the fiberoptic laser delivery device 200.

[0055] The infrared sensor 420 is also utilized in the function of a
proximal surface protection system. The proximal end 202 of the optical
fiber 204 can become contaminated or damaged during handling,
installation or operation, leading to overheating of the optical fiber
204 near the proximal end 202 when the laser source 100 is operating. If
left unchecked, this could result in damage to the fiberoptic laser
delivery device 200 and the optical system 440 as well. The laser driver
and control system 410 monitors the signal from the infrared sensor 420
and, if the signal exceeds a third temperature threshold T3, it
immediately shuts off power to the laser source 100 and alerts the user.
The signal for the third temperature threshold T3 can be distinguished
from the signals for the first and second temperature thresholds T1, T2
because the signal strength is generally an order of magnitude higher, in
part because the signal is not attenuated by passage through the optical
fiber 204. Alternatively, a separate infrared sensor or other temperature
sensor can be used to monitor the temperature of the proximal end 202 of
the optical fiber 204.

[0056] Optionally, the optical system 440 may also include a blast shield
432, which is a sacrificial optical element interposed between the
optical system 440 and proximal end 202 of the optical fiber 204. The
blast shield 432 protects the components of the optical system 440 in
case of thermal damage to the optical fiber 204. In a preferred
embodiment, the blast shield 432 is rotatably mounted so that it can be
used multiple times before it is replaced. An optional blast shield
protection system includes an infrared sensor 434 or other temperature
sensor that monitors the temperature of the blast shield 432. If the
temperature of the blast shield 432 exceeds a predetermined threshold
temperature, the laser driver and control system 410 will rotate the
blast shield 432 so that a clean area of the blast shield 432 is
presented to the laser beam. The laser driver and control system 410 may
use the occurrence of blast shield overheating in determining the power
level for operating the laser source 100. If the blast shield 432
overheats twice in close succession, the laser driver and control system
410 will shut off power to the laser source 100 and alert the user that
there is a likely problem with the fiberoptic laser delivery device 200.

[0057] The signal from the visible light sensor 454, which is indicative
of the visible light intensity returning from the optical fiber 204, is
utilized by the laser driver and control system 410 in the function of a
scope protection system. When the laser treatment system is operated
through the working channel of an endoscope, such as the cystoscope 300
shown in FIG. 4, it is very important that the laser source 100 not be
activated while the beam-emitting tip 208 is inside of the endoscope.
This could result in significant damage to the endoscope, requiring
expensive repairs to the scope. The endoscope includes an illumination
system that is generally always on when the endoscope is inserted into a
patient. Visible light from the endoscope's illumination system will
enter the fiberoptic laser delivery device 200 through the beam-emitting
tip 208 and travel back through the optical fiber 204 to the optical
system 440 where it is detected by the visible light sensor 454. However,
when the beam-emitting tip 208 of the fiberoptic laser delivery device
200 is withdrawn into the working channel of the endoscope, the light
from the illumination system is occluded and the signal from the visible
light sensor 454 is reduced. The laser driver and control system 410
monitors the signal from the visible light sensor 454 and when it drops
below a certain value, it shuts off power to the laser source 100 and
alerts the user.

[0058] Preferably, the laser driver and control system 410 will also be
configured to determine the derivative, that is the rate of change, of
the visible light returning through the optical fiber 204. As the optical
fiber 204 degrades during use, the amount of visible light returning
through the optical fiber 204 will gradually diminish, which should not
trigger the scope protection system. The scope protection system will
only shut off power to the laser source 100 if the signal from the
visible light sensor 454 drops at a rate above a certain threshold,
indicating that the beam-emitting tip 208 of the fiberoptic laser
delivery device 200 has been withdrawn into the working channel of the
endoscope.

[0059] The signal from the visible light sensor 454 is also utilized by
the laser driver and control system 410 in the function of a fiber
breakage detector. When the core of the optical fiber 204 breaks or burns
through because of excessive mechanical or thermal stress, the signal
from the visible light sensor 454 will abruptly drop because the visible
light will not be coupled back across the break. When this is detected,
the laser driver and control system 410 will shut off power to the laser
source 100 and alert the user of the fault. Fiber breakage can generally
be distinguished from withdrawing the fiberoptic laser delivery device
200 into the working channel of the endoscope by the abruptness of the
change in the signal.

[0060] Optionally, the laser treatment system may be configured with the
infrared sensor 420 and the visible light sensor 454 combined as a single
component housing both sensors.

[0061] Preferably, the laser treatment system will also include one or
more ambient beam sensors (ABS) located on the outside of the laser
system enclosure, which send a signal to the laser driver and control
system 410 indicating that light in the wavelength of the laser source
has been detected outside of the treatment area. When this is detected,
the laser driver and control system 410 will shut off power to the laser
source 100 and alert the user of the fault. Preferably, the ambient beam
sensors are located such that 360 degrees of the environment is
monitored. This can be accomplished with a plurality of sensors mounted
around the laser source or with a single sensor mounted at the highest
point of the laser source, giving it a 360 degree view of the
environment. The operation of the ambient beam sensors will be user
controlled so that this protection system can be turned off when the
laser system is used to perform surgery external to the patient. In the
case of external surgery some stray laser energy is to be expected.

[0062] Another feature of the invention that can be implemented by the
laser driver and control system 410 is in the nature of a heads-up
display of the laser treatment system status. While operating with the
laser treatment system, the surgeon will of necessity have his or her
attention focused on the video display monitor of the video endoscope (or
the ocular of the endoscope, if a standard optical endoscope is used) and
therefore will not be able to monitor other visual displays located on
the laser source or elsewhere for information about the system status. To
resolve this difficulty, certain critical information about the system
status can be displayed within the surgeon's visual field by modulating
the aiming beam of the laser treatment system. For example, using the
standard 532 nm green aiming laser 446 previously described, the aiming
laser will display a continuous beam of light when all aspects of the
system are operating within predetermined parameters. However, when the
laser driver and control system 410 detects an approaching fault with the
laser system, such as the fiberoptic laser delivery device 200 is nearing
the end of its useful life, the aiming laser can switch to a slow
flashing mode to alert the user of the change in status without drawing
attention away from the surgical site. If the condition reaches a
critical state, for example one that requires shutdown of the laser
source, the aiming laser can switch to a fast blinking mode to alert the
user. Information can also be displayed by using two or more colors of
aiming laser. For example, a green aiming laser can be used to indicate
"all systems go" and a red aiming laser can be used to indicate a system
fault. Another color aiming laser, for example blue, can be used to
indicate an approaching fault or other system status information. Other
information and/or finer gradations in the system status can be displayed
by using different flashing modes as described above or by combining or
alternately flashing the different colors of aiming lasers.

[0063] FIG. 5 is a longitudinal cross section of a distal portion of a
straight tip fiberoptic laser delivery device 200 as used in the
apparatus and method of the present invention for contact laser ablation
of tissue. As described above, the fiberoptic laser delivery device 200
includes a beam-emitting tip 208 located adjacent the distal end 210 of
the optical fiber 204. In this embodiment, the device has a straight
beam-emitting tip 208 ending in a beam-emitting distal surface 920. The
cladding 918 is stripped back and the distal end 210 of the optical fiber
204, which typically has a quartz core of approximately 600 microns
diameter, is fused to a larger diameter fiber tip member 212. The fiber
tip member 212 may be fabricated by fusing a separate plug of quartz
material to the distal end 210 of the optical fiber 204 or, more
preferably, the distal end 210 may simply be melted and allowed to form
into a ball or plug shape. The exterior of the fiber tip member 212 is
fused to a quartz tube 914, which surrounds the fiber tip member 212.
Forming the larger diameter fiber tip member 212 and fusing it to the
quartz tube 914 can be accomplished in a single step, if desired. The
quartz tube 914 is a hollow cylinder with an inside diameter just large
enough to pass over the fiber tip member 212 during assembly and an
outside diameter that is preferably approximately 2 mm. In the example
shown, the quartz tube 914 is approximately 1-2 cm long. By fusing the
distal end 210 of the quartz core optical fiber 204 to the fiber tip
member 212 and the quartz tube 914, an optical path is created that is
free of any changes in refractive index that would result in transmission
losses of the laser beam. The high efficiency of laser beam transmission
from this arrangement has two beneficial results: the most laser energy
possible is delivered to the tissue through the beam-emitting distal
surface 920 for effective tissue vaporization, and lower transmission
losses minimize the heating of the beam-emitting tip 208. In addition,
the expanded surface area of the beam-emitting distal surface 920 and the
increased thermal mass of the beam-emitting tip 208 also contribute to
reducing the temperature of the beam-emitting tip 208 during use, all of
which results in a longer usable life for the fiberoptic laser delivery
device 200. The expanded diameter of the beam-emitting tip 208 places
more surface area in contact with the tissue, which is beneficial for
tissue vaporization. Furthermore, the additional mass of the
beam-emitting tip 208 provides some sacrificial material to compensate
for the erosion of the beam-emitting distal surface 920, which is
inevitable when operating the laser treatment system at high power in
contact with tissue. The sacrificial material protects the core of the
optical fiber 204 from catastrophic failure and lengthens the usable life
of the fiberoptic laser delivery device 200.

[0064] The fiberoptic laser delivery device 200 can be constructed in
other sizes and materials if desired, as long as the basic design
considerations are adhered to. To reduce transmission losses and minimize
heating of the device, the optical fiber 204 should be made of a material
that efficiently transmits the chosen laser wavelength and the fiber tip
member 212 and the tube 914 should be made of compatible optical
materials that are fusible with the optical fiber 204 and have closely
matching refractive indices. Making all of the optical components from
the same material also has the effect of reducing the thermal stresses in
the device because all of the components will have the same thermal
expansion coefficient.

[0065] FIG. 6 is a longitudinal cross section of a bent tip fiberoptic
laser delivery device 200 for use with the laser system 100 of the
present invention for contact laser ablation of tissue. This embodiment
is particularly well adapted for treatment of benign prostatic
hyperplasia using the C-LAP method. In this embodiment, the device has an
angled beam-emitting tip 208 with an angled distal portion 910 ending in
a beam-emitting distal surface 920. Similar to the straight tip
embodiment described above, the distal end 210 of the optical fiber 204
is fused to a larger diameter fiber tip member 212 that has a diameter
that is greater than the diameter of the optical fiber 204. The fiber tip
member 212 may be fabricated by fusing a separate plug of quartz material
to the distal end 210 of the optical fiber 204 or, more preferably, the
distal end 210 may simply be melted and allowed to form into a ball or
plug shape. The exterior of the fiber tip member 212 is fused to a quartz
tube 914, which surrounds the fiber tip member 212. A bend 912 is formed
in the quartz tube 914 to create the angled distal portion 910 by heating
and bending the quartz tube 914 and the optical fiber 204. The angled
distal portion 910 allows the user to keep the beam-emitting distal
surface 920 in contact with the tissue when performing the C-LAP
procedure. The angled distal portion 910 increases the surface area of
the beam-emitting tip 208 in contact with the tissue.

[0066] FIG. 7 is a longitudinal cross section of another fiberoptic laser
delivery device 200 for use with the laser system 100 of the present
invention for tissue vaporization treatment of benign prostatic
hyperplasia. In this embodiment, the device has a side-firing tip 932
with an angled reflective surface 934 that redirects the laser beam out
through a beam-emitting lateral surface 936. The distal end 210 of the
optical fiber 204 is fused to a larger diameter fiber tip member 212 that
has a diameter that is greater than the diameter of the optical fiber
204. The fiber tip member 212 may be fabricated by fusing a separate plug
of quartz material to the distal end 210 of the optical fiber 204 or,
more preferably, the distal end 210 may simply be melted and allowed to
form into a ball or plug shape. An angled reflective surface 934 is
formed on the end of the larger diameter fiber tip member 212. This
results in a larger diameter reflective surface 934 that prevents the
loss of laser energy out the distal end of the side-firing tip 932 or at
the acute angle where the reflective surface 934 meets the outer diameter
of the fiber tip member 212. The angled reflective surface 934 may simply
be a polished surface backed by a lower refractive index material, such
as air, so the laser beam is redirected by total internal reflection.
Alternatively, the reflective surface 934 may be formed by depositing
gold, silver or another reflective coating, such as a multilayer
dielectric coating, on the polished angled surface. The reflective
surface 934 may be polished flat or it may be polished into a concave or
convex surface for focusing or defocusing of the laser beam, as desired.
The more reflective the reflective surface 934 is at the chosen
wavelength, the lower the reflective losses will be and the lower the
thermal stresses will be on the device 200 during use. The exterior of
the fiber tip member 212 is fused to a quartz tube 914, which surrounds
the fiber tip member 212. Particularly if total internal reflection is
used, the distal end 942 of the quartz tube 914 is fused closed to
enclose a gap 938 between the reflective surface 934 and the quartz tube
914 that is filled with air or, more preferably, a gas or gas mixture
with a low index of refraction and a low coefficient of thermal
expansion.

[0067] FIG. 8 is a longitudinal cross section of another fiberoptic laser
delivery device 200 for use with the laser system 100 of the present
invention for tissue vaporization treatment of benign prostatic
hyperplasia. This embodiment is similar to the embodiment of FIG. 7 with
a side-firing tip 932, except in this case the angled reflective surface
934 directs the laser beam out through a lens 940 on the lateral surface
936 of the device. Preferably, the lens 940 is formed of quartz and is
fused directly to the lateral surface 936 of the device to minimize
transmission losses. The lens 940 provides additional sacrificial
material at the point of tissue contact without significantly increasing
the bulk of the side-firing tip 932. Optionally, the lens 940 may be
shaped to focus or defocus the output beam, as desired. Alternatively, if
higher focusing power is needed, a higher refractive index material may
be used for the lens 940. In this case, an anti-reflective coating may
optionally be used between the lateral surface 936 of the device and the
focusing lens 940 to reduce transmission losses and to reduce thermal
stresses on the device in use.

[0068] The method of contact tissue vaporization of the present invention
has a number of advantages over the prior art approaches that use
non-contact tissue vaporization. Direct contact allows efficient
transmission of laser energy to the tissue without it being absorbed by
the irrigation fluid or by turbidity in the irrigation fluid that occurs
during some laser ablation methods. Maintaining a close spacing between
the laser delivery device and the tissue without inadvertent contact is
quite challenging, whereas the simple pull-back motion used in the
contact tissue vaporization method is easier to perform and has a much
quicker learning curve for urologists who have been trained in the
classic TURP technique. However, the contact tissue vaporization method
places quite a bit more thermal stress and mechanical stress on the laser
delivery device. It is a major inconvenience to the user to have a
procedure interrupted because the laser delivery device has failed or has
become too ineffective to achieve tissue vaporization. In addition, users
will resist the additional cost of replacing the laser delivery device
midway through a procedure. Success of the contact tissue vaporization
method depends in large part on using a laser with the correct wavelength
and power output for tissue vaporization, coupled with a more durable and
efficient laser delivery device. More efficient laser transmission and
distribution of any heat generated will reduce the thermal stress on the
laser delivery device and a more durable construction will help it to
resist both thermal and mechanical stresses. The fiber tip protection
system greatly enhances the contact tissue vaporization method by
prolonging the usable life of the laser delivery device while optimizing
the delivery of laser energy for effective tissue vaporization.

[0069] FIGS. 9A-9C illustrate representative steps for performing contact
laser ablation of the prostate using the apparatus and methods of the
present invention. As shown in FIG. 9A, the tubular insertion portion 302
of a cystoscope 300 or other endoscope is introduced through the urethra
304. A working lumen in the tubular insertion portion 302 of the
cystoscope 300 provides access to the enlarged prostate 310 for insertion
of a fiberoptic laser delivery device 200, such as that shown in FIG. 2.

[0070] In the next step, shown in FIG. 9B, the laser source is activated
to deliver laser energy through the fiberoptic laser delivery device 200
with the beam-emitting tip 208 in contact with the prostate tissue 306
that is obstructing the urethra 304. The fiberoptic laser delivery device
200 can be used to create a flow channel through the prostate gland by
vaporizing tissue that is obstructing the urethra. In addition, the
fiberoptic laser delivery device 200 can be used to debulk the enlarged
prostate by removing additional tissue 306 leaving a fully treated, open,
hollow and clear prostate portion 310. As a result, the prostate can be
left fully opened, hollowed out and essentially rendered less restrictive
of flow of fluids through the open prostate 310, as shown in FIG. 9C.

[0071] FIGS. 10A-10D illustrate an example of one preferred method of
performing C-LAP according to the present invention. The fiberoptic laser
delivery device 200 is advanced through the working channel of a
cystoscope placed in the patient's urethra 800 and into the prostate
gland, as described in connection with FIG. 9A. The beam-emitting tip 208
of the fiberoptic laser delivery device 200 is advanced past the
narrowing of the urethra in the prostate gland. Then, the laser source
100 is activated and the fiberoptic laser delivery device 200 is pulled
back through the area of the prostate gland to be treated with the
beam-emitting tip 208 in contact with the tissue. FIG. 10A shows a cross
section of the enlarged prostate gland after one pass of the fiberoptic
laser delivery device 200. The laser energy has vaporized a trough 800A
of prostatic tissue contacted by the beam-emitting tip 208. In addition,
the laser energy has created a thin layer of beneficial tissue
coagulation surrounding the trough 800A. The depth of the tissue
coagulation layer will depend on the laser wavelength and power setting,
as well as the configuration and condition of the beam-emitting tip 208.
Generally, the laser driver and control system 410 will strive to operate
the laser source 100 so as to maximize the ratio of tissue vaporization
to tissue coagulation given the parameters of the user-selected power
level and the operating condition of the fiberoptic laser delivery device
200.

[0072] A single pass of the fiberoptic laser delivery device 200 may be
enough to provide symptomatic relief in some patients, however additional
passes of the device will typically be needed. The beam-emitting tip 208
of the fiberoptic laser delivery device 200 is again advanced past the
narrowing of the urethra in the prostate gland, and the laser source 100
is activated while the fiberoptic laser delivery device 200 is pulled
back with the beam-emitting tip 208 in contact with the tissue. FIG. 10B
shows a cross section of the enlarged prostate gland after a second pass
of the fiberoptic laser delivery device 200. The laser energy has
vaporized a second trough 800B of prostatic tissue with a thin layer of
beneficial tissue coagulation surrounding the trough 800B. The second
trough 800B may be created immediately adjacent to the first trough 800A
so that the two troughs are contiguous. Thus, multiple passes of the
fiberoptic laser delivery device 200 can be used to create an enlarged
passage through the prostate gland.

[0073] Alternatively, the second trough 800B may be spaced apart from the
first trough 800A, as shown in FIG. 10B. Depending on the laser
wavelength and other parameters, much of the tissue between the two
troughs may be coagulated, as illustrated in FIG. 8C. The zones of
coagulation 800C are beneficial in preventing internal bleeding from the
inside of the healthy remaining prostatic tissue 310. The zones of
coagulation 800C are essentially cauterized surfaces extending a shallow
layer into the prostate, but not deep enough to interfere with the
viability and normal function of the prostate 310.

[0074] The coagulated tissue may simply be left to slough off after
surgery, which further enlarges the passage through the prostate gland.
However, for immediate symptomatic relief, it would be preferably to
remove the tissue between the two troughs at the time of surgery. In one
variation of this method which is describe further below, this can be
accomplished by combining the C-LAP procedure with a TURP procedure to
remove the coagulated tissue. The tissue between the two troughs can also
be efficiently removed with a third pass of the fiberoptic laser delivery
device 200, as illustrated in FIG. 10D. The fiberoptic laser delivery
device 200 is positioned within one of the troughs previously created at
the base or deepest point of the trough with the beam-emitting tip 208
oriented toward the other trough. The laser source 100 is activated while
the fiberoptic laser delivery device 200 is pulled back with the
beam-emitting tip 208 in contact with the tissue. This vaporizes a trough
800D that joins the base of the first trough 800A with the base of the
second trough 800B. At the same time, it excises a portion of the tissue
810 between the two troughs. The result is a much more efficient rate of
tissue removal using the fiberoptic laser delivery device 200. This
provides the additional benefit of shortening the duration of the C-LAP
procedure. This benefits the health care provider by making more
efficient use of hospital facilities and staff and it benefits the
patient by reducing anesthesia time while simultaneously providing more
effective symptomatic relief. If desired, a fourth and a fifth pass of
the fiberoptic laser delivery device 200 can be used to excise an
additional portion of tissue. These steps can be repeated as many times
as necessary for debulking especially large prostate glands.

[0075] In another method of using the system of the present invention, the
C-LAP can be combined with a modified TURP procedure that uses a hot loop
or wire resecting tool. FIG. 11 is a representative schematic
illustration of a wire loop 350 for performing TURP in conjunction with
the method and apparatus for C-LAP of the present invention. In this
representative embodiment, the wire loop 350 has a resistive heating
portion 352 with a beveled cutting edge 353. As current flows to the
resistive heating portion 352 through wire feeds 354, heat is produced.
Insulation 356 serves to protect and thermally and electrically insulate
wire feeds 354 as the wire loop tool 350 is inserted through a lumen 302
of an endoscope or other access cannula.

[0076] Many of the lasers usable for the contact laser ablation procedure
described herein produce a beneficial layer of tissue coagulation
surrounding the areas where tissue has been vaporized. In addition, the
laser source 100 can be operated at a power level below the tissue
vaporization threshold to create a deeper layer of coagulated tissue, if
desired. The laser treatment can then be followed by use of the loop or
hot wire to scrape away additional tissue. This combined use of contact
laser ablation and a modified TURP procedure is particularly useful for
quickly debulking especially large prostate glands. Unlike the standard
TURP procedure, this modified TURP procedure is virtually bloodless
because of the tissue coagulation produced by the laser.

[0077] Unless defined otherwise, all technical and scientific terms used
herein have the same meaning as commonly understood by one of ordinary
skill in the art to which the present invention belongs. Although any
methods and materials similar or equivalent to those described can be
used in the practice or testing of the present invention, the preferred
methods and materials are now described. All publications and patent
documents referenced in the present invention are incorporated herein by
reference.

[0078] While the principles of the invention have been made clear in
illustrative embodiments, there will be immediately obvious to those
skilled in the art many modifications of structure, arrangement,
proportions, the elements, materials, and components used in the practice
of the invention, and otherwise, which are particularly adapted to
specific environments and operative requirements without departing from
those principles. The appended claims are intended to cover and embrace
any and all such modifications, with the limits only of the true purview,
spirit and scope of the invention.